A mother is fighting for custody of her surviving son while the father tearfully said he's not guilty of murdering their younger child.

Donald Nelson and his girlfriend Moneesha Camp are charged with murdering Nelson's three-year-old son last week.

Nelson actually had to make two court appearances Tuesday and he cried at both of them. But these weren't his first trips to the courthouse, leaving many to wonder why he even had two little boys in his care.

Donald Nelson's face betrayed some concern as police found his three-year-old son Zion naked and lifeless in the back seat of his car Thursday.

Five days later, his face looked straight down, his eyes filled with tears, and he openly wept as he pleaded not guilty to murdering the boy.

"I've never had a client who was so upset, who cried so deeply, I was just moved by his reaction to the charges today," said Nelson's public defender, Margarita Martinez-Baly.

A judge wouldn't let Action News record Nelson and Moneesha Camp as they entered their pleas Tuesday.

Minutes after the criminal hearing, Nelson moved to another courtroom where Zion's mother is fighting for custody of their surviving five-year-old son.

"It was emotional," said Tiara Larson. "He was, you know, acting like he was sorry. He told me, you know, to take care of him if he gets placed with me."

Larson won the right to bury her younger son, but she'll have to wait at least one more day before CPS allows her to take the older boy out of foster care.

Larson says she tried to warn the agency about Nelson's propensity to violence -- she even asked for and got a welfare check last April, but agents decided the kids were okay.

Police say Nelson coached the boys to lie about abuse in their home. But Nelson also had a verifiable history of violence, including convictions for battery in 2009 and spousal abuse in 2010. The abuse victim was Larson and even though Zion wasn't born at the time, it may have been the boy's first exposure to violence.

"He beat me up, spent only two weeks in jail even though I was pregnant with bruises all over me and got three years misdemeanor probation," Larson said.

"Were you pregnant with Zion at the time?" an Action News reporter asked.

"Yes," she replied. "And they ordered him then, no contact with me or the child and yet just a year and a half later, they gave him custody of the child."

Camp was also in tears in court Tuesday afternoon, but she was a little more composed and she was obviously avoiding eye contact with Nelson.